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Empirical additive parameter and automatic assignment of 13 C NMR signals of some aryl and heteroaryl groups. A new criterion for a linear relationship between 13 C chemical shifts and charge densities
Author(s) -
Bangov Ivan P.,
Radeglia Reiner
Publication year - 1983
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/omr.1270210709
Subject(s) - chemical shift , substituent , chemistry , aryl , linear correlation , charge (physics) , linear relationship , spectral line , stereochemistry , mathematics , physics , organic chemistry , statistics , quantum mechanics , alkyl
The 13 C NMR signals of some mono‐ and disubstituted aryl compounds were assigned by means of empirical additive substituent parameters and information taken from fully coupled spectra. This assignment was compared with that obtained with the help of the method of automatic assignment of the signals based on the linear relationship between 13 C chemical shift and charge density. The results show that in the cases of XR substituents (X = O, NH and R = H, CH 3 , CH 2 CH 2 OH) a good correlation is observed and the automatic assignment is correct. In contrast, in the cases of CH 2 CH 2 Y substituents (Y = OH, NH 2 , Cl) a worsening of the correlation is observed and the automatic assignment is not correct. It is suggested that for compounds with a preliminarily known assignment, the automatic assignment can serve as an additional criterion for the reliability of the linear relationship between 13 C chemical shift and charge density.